The rails of a railroad track are usually secured to cross ties by spikes driven into tie plates, with the tie plates located between the rail and the tie, and the head of the spike overlapping the bottom of the rail. The tie plates block lateral movement of the rails, and anchors attached to the rail on either side of the tie are used to secure the rail against longitudinal movement.
Railroad ties occasionally must be replaced due to wear. When a tie must be replaced, the spikes are first removed. Next, the anchors are spread away from the ties to provide space for removal of the old tie and insertion of the new tie.
Various methods of removing and/or spreading rail anchors are known in the industry. One example is U.S. Pat. No. 4,890,558, issued to D. C. Quella et al. on Jan. 2, 1990. This patent describes an anchor spreader having a head assembly with a pair of telescoping spreader plates, controlled by hydraulic cylinders, for pushing the anchors away from the ties. The head assembly includes stop members to control the height of the head during an anchor-spreading operation. A rail clamp prevents longitudinal movement of the head during an anchor-spreading operation.
U.S. Pat. No. 4,903,611, issued to J. D. Holley on Feb. 27, 1990, describes an anchor-spreading mechanism having an anchor-spreading head, and a rail clamp. The vertical position of the head is controlled by a hydraulic cylinder. After lowering the head and clamping the rail, horizontal hydraulic cylinders located adjacent to the pusher, and in close proximity to the ballast, cause a pusher to be moved back and forth, pushing the tie plate off the tie in one direction, and then the other direction, thereby moving the anchors away from the tie.
U.S. Pat. No. 5,074,219, issued to J. Theurer et al. on Dec. 24, 1991, describes a rail anchor removing vehicle having the carrier arms for the anchor remover heads directly below the cab. The cab of the vehicle has a transparent floor. The carrier frame rests on a flanged wheel that rolls along the rail during the anchor removal operation. Each anchor remover head includes a hammer for driving the field side of the anchor downward, and a stripping element for pulling the anchor out from under the track, towards the gauge side. The hammer may include a horizontal portion for driving the anchor downward, and a vertical portion for driving the anchor toward the gauge side of the rail. A magnetic anchor-collecting drive retrieves the anchors and transfers them to a conveyor, which transports them to a storage container.
U.S. Pat. No. 5,117,760, issued to R. Almarez et al. on Jun. 2, 1992, describes a rail anchor spreader having a pair of spreader bars with interchangeable spreader plates at their tips for engaging different rail anchors. A limit switch controls the vertical positioning of the spreader assembly. Each spreader bar is pulled outward by a hydraulic cylinder to move its anchor, with its limit of travel set by placing a threaded bolt at the maximum outward travel position.
U.S. Pat. No. 5,277,122, issued to R. Almaraz et al. on Jun. 11, 1994, describes a rail anchor adjuster for moving railway anchors towards the tie. The anchor adjuster includes a pair of pivoting arms having top ends connected by a hydraulic cylinder, and bottom ends dimensioned and configured to engage the rail anchors. The height of the anchor adjuster assembly is controlled by interchangeable stop pads.
U.S. Pat. No. 5,438,931, issued to N. W. Becker et al. on Aug. 8, 1995, describes a rail anchor remover having a telescoping ram assembly for driving the tail of the anchor below the base of the rail, a kicker assembly for driving the anchor transversely under the rail towards the gauge side of the rail, and a window assembly for driving the anchor away from the rail.
U.S. Pat. No. 5,546,864, issued to W. Straub et al. on Aug. 20, 1996, describes a rail anchor remover having a reciprocating pusher for pushing the anchor downward away from the rail, and a reciprocating scraper for pulling the anchor out from under the rail. Proximity switches are used to monitor the position of the pusher and scraper. A similar device is described in U.S. Pat. No. 5,730,060 also issued to W. Straub et al., on Mar. 24, 1998.
U.S. Pat. No. 5,915,744, issued to S. G. Cotsford on Jun. 29, 1999, and assigned to Harsco Corporation, the assignee of the present invention, describes a rail anchor removal machine and method using anchor-removing rollers, and a conveyor system for moving the removed anchors to the side of the railroad track. The anchors are removed by angled rollers as the rail is raised, which push the anchors downward and towards the gauge side of the track as they roll over the anchor. A funnel-like anchor catch deflects the removed anchors towards a conveyor, which deposits them alongside the track.
U.S. Pat. No. 6,662,729, issued to H. Madison on Dec. 16, 2003, and assigned to Harsco Corporation, the assignee of the present invention, describes a railway anchor spreader with a rotating plate on each side of each rail, with the bottom of each rotating plate having a pair of jaws. The tie plates are lowered until the jaws strike the ballast, and the tie plates are then pivoted first in one direction, and then in the opposite direction, by a hydraulic cylinder located near the top of the anchor spreader plates. The jaws will thereby strike the tie plates, first pushing them in one direction and then in the opposite direction, to move the rail anchors away from the tie.
Many of the above-described patents propose devices requiring that the height of the anchor spreader be adjusted and set each time it is used with a different height rail. Furthermore, the means for properly positioning the anchor spreader must, in addition to properly positioning the spreader, ensure that movement of the spreader to spread the anchors does not pose a risk of striking the ties. Accordingly, there is a need for an anchor spreader capable of being used with multiple heights of rail without adjustments. Additionally, there is a need for an anchor spreader which can be moved into position without striking the anchor or other components of the railway. Further, some of the above-described references position hydraulic cylinders relatively close to the ballast surrounding the ties, resulting in the potential for interference between this ballast and the hydraulic cylinders. Accordingly, there is a need for a railway anchor spreader having hydraulic cylinders and other components kept away from the ballast.
While the prior art describes many types of spike pullers and anchor spreaders, these devices are positioned on separate and distinct pieces of maintenance equipment, with each of the equipment requiring at least on operator for operation. There is a need, therefore, for a railway maintenance vehicle which combines the function of a spike puller and an anchor spreader, thereby eliminating the expense of different maintenance vehicles and reducing the number of operators required to perform the maintenance.